Green made his professional mixed martial arts debut in January 2008. He quickly amassed an 8-1 record while fighting on independent events throughout California and Mexico and did not train for his first "12 or 13" fights.[6]

On July 14, 2011, it was announced that Green had signed a four-fight deal with Strikeforce. It was originally announced that Green would debut against Milton Vieira at Strikeforce Challengers: Gurgel vs. Duarte.[9] However, on July 19, it was announced he would be filling in for Lyle Beerbohm against Gesias Cavalcante at Strikeforce: Fedor vs. Henderson.[10] The fight was very back and forth, but Green lost the fight via a narrow split decision.

His next bout came against Charon Spain at Strikeforce Challengers: Larkin vs. Rossborough. Green won the fight via submission (arm-triangle choke) in the second round but is out indefinitely due to left and right hand injuries.[11]

Green was scheduled to face Isaac Vallie-Flagg at Strikeforce Challengers: Britt vs. Sayers. However, Vallie-Flagg was forced out of the bout with an injury and replaced by J.P. Reese. He won the fight via submission in the third round.

Green defeated Jacob Volkmann on February 2, 2013 at UFC 156 via rear naked choke in round three.[12] After back and forth action in the first two rounds, Green displayed some great grappling, countering Volkmann's attempts and finishing with the choke after some vicious ground and pound, which forced Volkmann to give up his back. The performance earned Green Submission of the Night honors.

Green faced James Krause on November 6, 2013 at UFC Fight Night 31.[15] The fight ended in unusual fashion as Green had previously kicked Krause in the groin area twice, resulting in a one point deduction. Green then landed a blow to Krause's belt line, which resulted in Krause falling to the canvas. Referee John McCarthy declared it a legal blow and awarded Green a TKO victory.

Green was expected to face Jim Miller on April 26, 2014 at UFC 172.[19] However, in the week leading up to the event, Green pulled out of the bout citing another injury and was replaced by Yancy Medeiros.[20]

The bout with Trujillo was rescheduled for August 2, 2014 at UFC 176.[21] However, after UFC 176 was cancelled, Green/Trujillo was rescheduled and was expected to take place on August 16, 2014 at UFC Fight Night 47.[22] Subsequently, Green was removed from this fight on July 11 in favor of a matchup with against Josh Thomson as Green replaced Michael Johnson on July 26, 2014 at at UFC on Fox 12.[23] Green won the bout via split decision.[24]